Java (as of version 6, aka 1.6) does not allow you to declare a static HashMap as conveniently as an array. Still, you have the alternative of using a static block in your class to add fields. Take this example:

This works fine. But then you want to map something a little more complex than a string to another string. And I don't mean something very complex... just, say, a string to a string and an integer (yes, you'd like to use some kind of "pair object", but it looks like Java does not have it).

So you go and try to do things The Java Way (tm) and create a tiny class just to hold your two values:

The error messages say that my "new" operators are failing due to the use of the "this" variable, which is not there at all! But hey, we can call "new" from a static context, can't we? We just did that when declaring the HashMap itself.

It turns out that the problem is that we're using an inner class. Objects from inner classes hold a "this" reference to their parent object (yes, as in myInnerObject.this.myParentAttribute... go figure), hence the trouble with the implicit "this" reference.

You have to make it a static inner class, which means it doesn't know anything about the enclosing class. Yes, that's yet another meaning for the word "static" in programming. Due to this peculiar meaning, inner classes are the only context where you can use the "static" qualifier to a class declaration in Java.